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Cited by 1,959Alzheimer's disease research and treatmentsDementia and Cognitive Impairment ResearchNeurological Disease Mechanisms and Treatments

Oxidative stress, dysfunctional glucose metabolism and Alzheimer disease

Open access
Butterfield, D. Allan, Halliwell, Barry·2019·Nature Reviews Neuroscience
DOI 10.1038/s41583-019-0132-6PMC PMC9382875
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Abstract

Alzheimer disease (AD) is a major cause of age-related dementia. We do not fully understand AD aetiology and pathogenesis, but oxidative damage is a key component. The brain mostly uses glucose for energy, but in AD and amnestic mild cognitive impairment glucose metabolism is dramatically decreased, probably owing, at least in part, to oxidative damage to enzymes involved in glycolysis, the tricarboxylic acid cycle and ATP biosynthesis. Consequently, ATP-requiring processes for cognitive function are impaired, and synaptic dysfunction and neuronal death result, with ensuing thinning of key brain areas. We summarize current research on the interplay and sequence of these processes and suggest potential pharmacological interventions to retard AD progression.

AI snapshot

Written from the paper’s full text.

TL;DR

This review argues that oxidative and nitrosative damage is a central driver of Alzheimer disease (AD) and amnestic mild cognitive impairment (aMCI), especially by impairing glucose metabolism and ATP production. It links these metabolic failures to synaptic dysfunction, neuronal death, insulin resistance, proteostasis failure, and disappointing antioxidant trials, while suggesting earlier biomarker-based and multifactorial interventions.

Key findings

  • Oxidative damage is elevated in preclinical AD, aMCI, and AD brain/CSF, including protein carbonyls, lipid peroxidation markers such as HNE and F2/F4-isoprostanes, 3-nitrotyrosine, and 8-OHdG; these changes appear in brain regions rich in Aβ plaques but not in plaque-free regions.
  • Glucose metabolism is markedly reduced in AD and aMCI, likely partly because glycolytic enzymes, TCA-cycle enzymes such as aconitase, creatine kinase, and ATP synthase are oxidatively modified; decreased ATP then impairs ion gradients, neurotransmission, Ca2+ homeostasis, and neuronal survival.
  • The review reports that about 15% of people with aMCI progress to AD annually, and that AD pathology can begin up to two decades before clinical symptoms; a cited plasma amyloid-β study discriminated control, aMCI, and AD samples with over 94% confidence.
  • In a cited aged-beagle study, 12-year-old dogs given a high-antioxidant diet, environmental enrichment, and exercise for three years had behavioral error rates, brain Aβ42 levels, and oxidative damage similar to 4-year-old dogs; the FINGER trial reported cognitive benefits from a two-year multidomain intervention, including in apoE4 carriers.

Methods

  • Narrative review synthesizing human, animal, and preclinical literature on oxidative stress, glucose metabolism, insulin resistance, proteostasis, Down syndrome, biomarkers, and interventions in AD and aMCI.
  • No primary data collection, systematic search strategy, or meta-analysis is described in the provided text.
  • The paper integrates findings from redox proteomics, biomarker studies, imaging cohorts such as DIAN, AIBL, and ADNI, and intervention trials including vitamin E, polyphenols, intranasal insulin, ketogenic approaches, and lifestyle programs.

Limitations

  • Stated: clinical trials of antioxidants such as vitamin E have been largely disappointing; vitamin E transport into brain is limited; polyphenols may act through mild pro-oxidant hormesis and could aggravate oxidative stress if overused; curcumin is a poor in vitro antioxidant and its true therapeutic value remains unclear; deuterated lipids and ketogenic approaches need more research; CSF biomarkers are proposed but not yet validated.
  • Stated: single interventions, such as vascular risk reduction in preDIVA or nutritional supplements, generally appear less effective than multifactorial approaches.
  • Evident from the text: this is a narrative review without a described systematic search or formal quality assessment, and many mechanistic claims rely on preclinical models, animal studies, or correlational human biomarker data rather than definitive causal human trials.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41583-019-0132-6

Cites

123 of 123 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

133 of 276 cited sources checked · 40 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    In preclinical Alzheimer disease and Alzheimer disease brains, oxidative damage to many molecules is elevated.

    “In the brains of subjects with PCAD and AD, levels of oxidative damage to a wide range of molecules are increased8–19.”
    Quote in the paperSubstantial claim3 of 10 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [9] Butterfield, D. A., Di Domenico, F. & Barone, E. Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochim. Biophys. Acta 1842, 1693–1706 (2014). source
    • cites [10] Cheignin, C. et al. Oxidative stress and the amyloid beta peptide in Alzheimer’s disease. Redox Biol. 14, 450–464 (2018). source

      Section 2.3.1 (page not provided) reports increased oxidation of proteins, lipids, DNA and RNA in AD brains. For preclinical AD, it specifically reports increased 8-hydroxyguanine in the hippocampus, but does not establish increased damage across a wide range of molecules at that stage. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [11] Halliwell, B. Oxidative stress and neurodegeneration: where are we now? J. Neurochem. 97, 1634–1658 (2006). source
    • cites [12] Butterfield, D. A. & Boyd-Kimball, D. Oxidative stress, amyloid β-peptide, and altered key molecular pathways in the pathogenesis and progression of Alzheimer’s disease. J. Alzheimers Dis. 62, 1345–1367 (2018). This paper highlights the role of Aβ42 oligomers in oxidative stress in aMCI and AD brains in in vitro and in vivo models and how redox proteomics-mediated identification of oxidatively modified key brain proteins is correlated with glucose dysmetabolism, dysfunction of the proteostasis network, activation of mTORC1 and altered protein phosphorylation, all contributing to neuronal death source

      The section “Oxidative stress in brain in subjects with AD and aMCI” (page unavailable) reports elevated protein oxidation, lipid peroxidation, and nitrosative damage in AD brain. It also reports elevated oxidative stress in amnestic mild cognitive impairment, but does not establish the claimed wide-ranging molecular damage specifically in brains of subjects with preclinical AD (PCAD); aMCI and PCAD are not interchangeable. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [13] Nourooz-Zadeh, J., Liu, E. H., Yhlen, B., Anggard, E. E. & Halliwell, B. F4-isoprostanes as specific marker of docosahexaenoic acid peroxidation in Alzheimer’s disease. J. Neurochem. 72, 734–740 (1999). source
    • cites [14] Di Domenico, F. et al. Oxidative signature of cerebrospinal fluid from mild cognitive impairment and Alzheimer disease. Free Radic. Biol. Med. 91, 1–9 (2015). source
    • cites [15] Di Domenico, F., Tramutola, A. & Butterfield, D. A. Role of 4-hydroxy-2-nonenal (HNE) in the pathogenesis of Alzheimer disease and other selected age-related neurodegenerative disorders. Free Radic. Biol. Med. 111, 253–261 (2017). source
    • cites [16] Lauderback, C. M. et al. The glial glutamate transporter, GLT-1, is oxidatively modified by 4-hydroxy-2-nonenal in the Alzheimer’s disease brain: Role of Aβ1-42. J. Neurochem. 78, 413–416 (2001). source
    • cites [17] Martins, R. N., Harper, C. G., Stokes, G. B. & Masters, C. L. Increased cerebral glucose-6-phosphate dehydrogenase activity in Alzheimer’s disease may reflect oxidative stress. J. Neurochem. 46, 1042–1045 (1986). source
  • Interpretationcitation

    Oxidative damage is a central component of Alzheimer disease pathogenesis.

    “but oxidative damage is a key component.”
    Quote in the paperSubstantial claim4 of 10 sources checked
    • cites [2] Martins, R. N. et al. Alzheimer’s disease: a journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies—gains from AIBL and DIAN cohort studies. J. Alzheimers Dis. 62, 965–992 (2018). This article provides a detailed review of how cohort studies have contributed to our understanding of AD. source
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [9] Butterfield, D. A., Di Domenico, F. & Barone, E. Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochim. Biophys. Acta 1842, 1693–1706 (2014). source
    • cites [10] Cheignin, C. et al. Oxidative stress and the amyloid beta peptide in Alzheimer’s disease. Redox Biol. 14, 450–464 (2018). source
    • cites [11] Halliwell, B. Oxidative stress and neurodegeneration: where are we now? J. Neurochem. 97, 1634–1658 (2006). source
    • cites [12] Butterfield, D. A. & Boyd-Kimball, D. Oxidative stress, amyloid β-peptide, and altered key molecular pathways in the pathogenesis and progression of Alzheimer’s disease. J. Alzheimers Dis. 62, 1345–1367 (2018). This paper highlights the role of Aβ42 oligomers in oxidative stress in aMCI and AD brains in in vitro and in vivo models and how redox proteomics-mediated identification of oxidatively modified key brain proteins is correlated with glucose dysmetabolism, dysfunction of the proteostasis network, activation of mTORC1 and altered protein phosphorylation, all contributing to neuronal death source
    • cites [13] Nourooz-Zadeh, J., Liu, E. H., Yhlen, B., Anggard, E. E. & Halliwell, B. F4-isoprostanes as specific marker of docosahexaenoic acid peroxidation in Alzheimer’s disease. J. Neurochem. 72, 734–740 (1999). source
    • cites [14] Di Domenico, F. et al. Oxidative signature of cerebrospinal fluid from mild cognitive impairment and Alzheimer disease. Free Radic. Biol. Med. 91, 1–9 (2015). source
    • cites [15] Di Domenico, F., Tramutola, A. & Butterfield, D. A. Role of 4-hydroxy-2-nonenal (HNE) in the pathogenesis of Alzheimer disease and other selected age-related neurodegenerative disorders. Free Radic. Biol. Med. 111, 253–261 (2017). source
    • cites [16] Lauderback, C. M. et al. The glial glutamate transporter, GLT-1, is oxidatively modified by 4-hydroxy-2-nonenal in the Alzheimer’s disease brain: Role of Aβ1-42. J. Neurochem. 78, 413–416 (2001). source
  • Premisecitation

    Type 2 diabetes, in which insulin resistance is a key feature, is a significant risk factor for Alzheimer disease.

    “Indeed, type 2 diabetes (T2DM), a key component of which is insulin resistance, is a significant risk factor for developing AD7.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [7] Arnold, S. E. et al. Brain insulin resistance in type 2 diabetes and Alzheimer disease: concepts and conundrums. Nat. Rev. Neurol. 14, 168–181 (2018). This paper is an excellent review of the links between AD, dysfunctional glucose metabolism and diabetes. source
  • Premisecitation

    Alzheimer disease pathology begins up to two decades before clinical symptoms appear.

    “AD pathology occurs well before (up to two decades) the onset of clinical symptoms2–4.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [2] Martins, R. N. et al. Alzheimer’s disease: a journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies—gains from AIBL and DIAN cohort studies. J. Alzheimers Dis. 62, 965–992 (2018). This article provides a detailed review of how cohort studies have contributed to our understanding of AD. source

      The DIAGNOSIS section says AD pathogenesis starts before symptoms, supporting the central claim. But it gives a window of 2–3 decades, rather than an upper limit of two decades; the INTRODUCTION also says pathology may take over two decades before symptoms appear. No page numbers are provided in the supplied passages. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [3] Markesbery, W. R. Neuropathologic alterations in mild cognitive impairment: a review. J. Alzheimers Dis. 19, 221–228 (2010). source
    • cites [4] Landau, S. M. & Frosch, M. P. Tracking the earliest pathological changes in Alzheimer disease. Neurology 82, 878–883 (2014). source
  • Interpretationcitation

    The accumulation of senile plaques and neurofibrillary tangles causes synaptic dysfunction, synapse loss, and eventual neuronal death.

    “leading to dysfunction and loss of synapses and eventual neuronal death1,2.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [1] Nelson, P. T., Braak, H. & Markesbery, W. R. Neuropathology and cognitive impairment in Alzheimer disease: a complex but coherent relationship. J. Neuropathol. Exp. Neurol. 68, 1–14 (2009). source

      In “The Neuritic Plaque: A Pathological Entity With Strong Mechanistic Implications” (page unavailable), the paper says neuritic plaques involve degenerating nerve-cell processes and that amyloid plaque pathology induces neurofibrillary pathology and apparent structural and functional disruption. In “Nonlinear clinicopathological correlations” (page unavailable), it suggests these changes may impair function before cell death. It does not establish the claimed sequence of synaptic dysfunction, synapse loss, and eventual neuronal death as a definite consequence of plaque and tangle accumulation. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [2] Martins, R. N. et al. Alzheimer’s disease: a journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies—gains from AIBL and DIAN cohort studies. J. Alzheimers Dis. 62, 965–992 (2018). This article provides a detailed review of how cohort studies have contributed to our understanding of AD. source

      The Introduction identifies amyloid plaques and neurofibrillary tangles as hallmarks of Alzheimer’s disease and reports widespread synaptic loss and neuronal death by the time of diagnosis. The Aβ imaging: PiB-PET section also describes synaptic failure and eventual neuronal loss as downstream mechanisms, but says these may be triggered by Aβ or not; it does not establish that accumulation of plaques and tangles causes the full sequence asserted. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
  • May combine two claims. 59
  • Classified as probably not a substantial claim. 6

  • May combine two claims.

    Premisecitation

    Glucose enters the brain through efficient transporters and needs insulin for optimal cellular use.

    “Glucose enters the brain from the vasculature through highly efficient glucose transporters and requires insulin for optimal cellular utilization7.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [7] Arnold, S. E. et al. Brain insulin resistance in type 2 diabetes and Alzheimer disease: concepts and conundrums. Nat. Rev. Neurol. 14, 168–181 (2018). This paper is an excellent review of the links between AD, dysfunctional glucose metabolism and diabetes. source

      The “Effects of insulin in neurons” section describes glucose uptake through GLUT3 and says insulin-regulated GLUT4 may improve glucose flux during high metabolic demand. It also explicitly says neuronal glucose uptake and utilization are influenced by insulin, not dependent on it. The source therefore does not support the general claim that optimal cellular use requires insulin. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Diabetes causes oxidative stress, which may contribute to the increased tendency for Alzheimer disease in diabetes.

    “Diabetes also leads to oxidative stress (ref8, also see later discussion), which may make a contribution to its propensity to favour AD development9.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [9] Butterfield, D. A., Di Domenico, F. & Barone, E. Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochim. Biophys. Acta 1842, 1693–1706 (2014). source

  • May combine two claims.

    Premisecitation

    Brain insulin resistance occurs in Alzheimer disease and amnestic mild cognitive impairment.

    “In AD and aMCI, however, brain insulin resistance is present6,7.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [6] Croteau, E. et al. A cross-sectional comparison of brain glucose and ketone metabolism in cognitively healthy older adults, mild cognitive impairment and early Alzheimer’s disease. Exp. Gerontol. 107, 18–26 (2018). source
    • cites [7] Arnold, S. E. et al. Brain insulin resistance in type 2 diabetes and Alzheimer disease: concepts and conundrums. Nat. Rev. Neurol. 14, 168–181 (2018). This paper is an excellent review of the links between AD, dysfunctional glucose metabolism and diabetes. source

      The section “Brain insulin resistance in ADRD, irrespective of T2DM” reports experimentally demonstrated brain insulin resistance in AD and insulin-signalling abnormalities in post-mortem brains from people with AD or MCI. It does not specify that the MCI cases were amnestic, so the aMCI-specific part of the claim is not established by our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Alzheimer disease is characterized by brain accumulation of senile plaques, composed mainly of fibrillary amyloid beta-peptide and dystrophic neurites, and neurofibrillary tangles, composed of hyperphosphorylated tau.

    “AD is characterized by an accumulation of senile plaques (SP) [composed mostly of fibrillary amyloid beta-peptide (Aβ) and dystrophic neurites] and neurofibrillary tangles (NFT) [composed of hyperphosphorylated tau protein] in the brain”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [1] Nelson, P. T., Braak, H. & Markesbery, W. R. Neuropathology and cognitive impairment in Alzheimer disease: a complex but coherent relationship. J. Neuropathol. Exp. Neurol. 68, 1–14 (2009). source

      Table 1 and the Figure 1 caption (both indexed under Summary and Conclusions; page unavailable) describe AD amyloid plaques as having a fibrillary amyloid-peptide core and neuritic plaques as surrounded by degenerating neurites. The caption says neurofibrillary tangles are composed of tau fibrils, but the available passages do not specify that the tau is hyperphosphorylated. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [2] Martins, R. N. et al. Alzheimer’s disease: a journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies—gains from AIBL and DIAN cohort studies. J. Alzheimers Dis. 62, 965–992 (2018). This article provides a detailed review of how cohort studies have contributed to our understanding of AD. source

      The Introduction (page unavailable) identifies amyloid plaques and neurofibrillary tangles as characteristic AD pathology and says plaques are mainly made of fibrillized amyloid-β while tangles are mostly made of hyperphosphorylated tau. It does not state that dystrophic neurites are a component of the plaques. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Alzheimer disease clinically involves progressive cognitive decline with memory loss and impaired higher executive function.

    “Clinically, AD is characterized by several features, notably a progressive cognitive decline involving loss of memory and higher executive functioning1.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [1] Nelson, P. T., Braak, H. & Markesbery, W. R. Neuropathology and cognitive impairment in Alzheimer disease: a complex but coherent relationship. J. Neuropathol. Exp. Neurol. 68, 1–14 (2009). source

  • May combine two claims.

    Premisecitation

    Glucose metabolism becomes dysfunctional in Alzheimer disease and amnestic mild cognitive impairment.

    “One important process that becomes dysfunctional in AD and aMCI is metabolism of glucose5,6.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [5] Weise, C. M. et al. Left lateralized cerebral glucose metabolism declines in amyloid-β positive persons with mild cognitive impairment. Neuroimage. Clin. 20, 286–296 (2018). source

      The Introduction describes declining regional cerebral glucose metabolism in AD, and the Conclusion reports such declines in amyloid-β-positive people with MCI. The paper does not identify its MCI group specifically as amnestic MCI, so it does not fully establish that part of the claim. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [6] Croteau, E. et al. A cross-sectional comparison of brain glucose and ketone metabolism in cognitively healthy older adults, mild cognitive impairment and early Alzheimer’s disease. Exp. Gerontol. 107, 18–26 (2018). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Defects in sirtuin 3 may contribute to oxidative damage in Alzheimer disease mitochondria.

    “there has been a suggestion that defects in sirtuin 3 (SIRT 3) contribute to oxidative damage in AD mitochondria37.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [37] Lee, J. et al. SIRT3 deregulation is linked to mitochondrial dysfunction in Alzheimer’s disease. Aging Cell 17, e12679 (2018). source

  • May combine two claims.

    Premisecitation

    Amyloid beta 42 oligomers contribute to synaptic dysfunction and impair learning and memory.

    “Aβ42 oligomers contribute to this synaptic dysfunction, impairing learning and memory31.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [31] Li, S. et al. Soluble oligomers of amyloid β-protein facilitate hippocampal long term depression by disrupting glutamate uptake. Neuron 62, 788–801 (2009). source

      The Results show that synthetic Aβ1-42 and other soluble Aβ preparations disrupt hippocampal synaptic plasticity, and the paper describes long-term potentiation as a correlate of learning and memory. It does not directly show that Aβ42 oligomers impair learning or memory; that part of the claim goes beyond the outcomes reported here. The indexed passages provide section labels but no page numbers. (LLM, conf=0.83)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    3-nitrotyrosine levels, indicating peroxynitrite damage, are elevated in Alzheimer disease and amnestic mild cognitive impairment.

    “Elevated levels of 3-nitrotyrosine (3-NT), suggestive of damage by peroxynitrite (Table 1) are also observed in AD18,24 and aMCI25.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [18] Smith, M. A., Richey Harris, P. L., Sayre, L. M., Beckman, J. S. & Perry, G. Widespread peroxynitrite-mediated damage in Alzheimer’s disease. J. Neurosci. 15, 2653–2657 (1997). source
    • cites [24] Reed, T. T., Pierce, W. M., Turner, D. M., Markesbery, W. R. & Butterfield, D. A. Proteomic identification of nitrated brain proteins in early Alzheimer’s disease inferior parietal lobule. J. Cell. Mol. Med. 13, 2019–2029 (2009). source
    • cites [25] Sultana, R. et al. Proteomic identification of nitrated brain proteins in amnestic mild cognitive impairment. J. Cell. Mol. Med. 11, 839–851 (2007). source

  • May combine two claims.

    Premisecitation

    Activated mTORC1 regulates protein synthesis, autophagy, mitochondrial function, lipogenesis, ketogenesis, and insulin signaling, is linked to glucose metabolism, and is activated by growth factors, amino acids, and high cellular energy status.

    “Activated mTORC1 is intimately involved in regulation of protein synthesis, autophagy, mitochondrial function, lipogenesis, ketogenesis, and insulin signaling, and is crucially linked to glucose metabolism, where it becomes activated by growth factors, amino acids, and high cellular energy status41,42 (Fig 2).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [41] Di Domenico, F. et al. mTOR in Down syndrome: role in Aβ and Tau neuropathology and transition to redox Alzheimer disease-like dementia. Free Radic. Biol. Med. 114, 94–101 (2018). source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Down syndrome phenotypes result from full or partial triplication of chromosome 21.

    “The varied phenotypes of DS result from full or partial triplication of chromosome 21, the most common human chromosomal disorder59.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [59] Lott, I. T. Neurological phenotypes for Down syndrome across the life span. Prog. Brain Res. 197, 101–121 (2012). source

      The Dementia section links Down syndrome to trisomy 21 and overexpression of a chromosome 21 gene, while the Neuroanatomic abnormalities section discusses effects of an extra chromosome 21 on development. These passages support a chromosome 21 basis for Down syndrome phenotypes, but the copy does not establish that partial triplication of chromosome 21 produces the varied human phenotypes; its reference to partial trisomy concerns mice. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Redox proteomics identified oxidatively damaged proteins in amniotic fluid that correlate with Down syndrome phenotypes, suggesting oxidative stress contributes to those phenotypes.

    “Redox proteomics has identified several oxidatively damaged proteins (including ceruloplasmin, transferrin, retinol-binding protein 4, apolipoprotein Al, complement C9, and collagen α−1Vchain) in amniotic fluid that correlate with the various phenotypes presented in individuals with DS, suggesting that oxidative stress contributes to these phenotypes64.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [64] Barone, E., Head, E., Butterfield, D. A. & Perluigi, M. HNE-modified proteins in Down syndrome: involvement in development of Alzheimer disease neuropathology. Free Radic. Biol. Med. 111, 262–269 (2017). source

      Section 4 reports increased HNE and an elevated GSSG/GSH ratio in amniotic fluid from Down syndrome pregnancies, supporting early oxidative stress. It does not identify the six named proteins as oxidatively damaged in amniotic fluid or report that they correlate with Down syndrome phenotypes. The section also says whether these peripheral changes are associated with intellectual disability has yet to be evaluated; no page number is available in our copy. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Impaired autophagy is present in early Alzheimer disease and is also found in amnestic mild cognitive impairment and preclinical Alzheimer disease brains.

    “This significant mediator of neuronal death is present in the early stages of AD, and evidence of impaired autophagy is also found in aMCI brain and PCAD brains41–43.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [41] Di Domenico, F. et al. mTOR in Down syndrome: role in Aβ and Tau neuropathology and transition to redox Alzheimer disease-like dementia. Free Radic. Biol. Med. 114, 94–101 (2018). source

      Section 2.1 (page unavailable) says autophagy is impaired in AD brains, supporting that part of the claim. It reports reduced autophagosome formation early in Down syndrome brains, not specifically in early AD, aMCI, or preclinical AD brains. The reference list names a study of mTOR signaling across preclinical AD, aMCI, and late-stage AD, but this paper does not state that impaired autophagy was found in those groups. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source
    • cites [43] Rabbani, N., Xue, M. & Thornalley, P. Dicarbonyls and glyoxalase in disease mechanisms and clinical therapeutics. Glycoconj. J. 33, 513–525 (2016). source

      The “Other diseases” section links dicarbonyl stress to Alzheimer’s disease through clinical biomarker studies, but does not discuss impaired autophagy or the early-AD, aMCI, and preclinical-AD brain groups in the claim. Searches for those terms and for autophagy found no passage addressing the attributed finding; page numbers were unavailable in our copy. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Degradation of oxidatively modified proteins remains compromised in Alzheimer disease brain because 20S proteasome activities are dysfunctional, including inhibition by amyloid beta, leading to accumulation of oxidatively modified, often misfolded and dysfunctional proteins.

    “Unfortunately, degradation of oxidatively modified proteins is still compromised in AD brain as the 20S proteasome enzymatic activities are dysfunctional51,52 (including inhibition by Aβ), resulting in accumulation of oxidatively modified, often misfolded and dysfunctional proteins.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [51] Tseng, B. P., Green, K. N., Chan, J. L., Blurton-Jones, M. & LaFerla, F. M. Abeta inhibits the proteasome and enhances amyloid and tau accumulation. Neurobiol. Aging 29, 1607–1618 (2008). source
    • cites [52] Mota, S. I. et al. Oxidative stress involving changes in Nrf2 and ER stress in early stages of Alzheimer’s disease. Biochim. Biophys. Acta 1852, 1428–1441 (2015). source

      Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    The oxidatively modified proteins in Down syndrome include proteins linked to altered glucose metabolism, mTOR signaling with inhibited autophagy and increased insulin resistance, and the proteostasis network.

    “These oxidatively modified, and likely dysfunctional, proteins include ones associated with altered glucose metabolism, mTOR signaling (including inhibited autophagy and increased insulin resistance), and the proteostasis network42,61,62,65,66.”
    Quote in the paperSubstantial claim3 of 5 sources checked
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source
    • cites [61] Perluigi, M. et al. Neuropathological role of PI3K/Akt/mTOR axis in Down syndrome. Biochim. Biophys. Acta 1842, 1144–1153 (2014). source

      The Discussion (page unavailable) reports oxidative modification of proteins in the proteostasis network, including components of protein-degradation pathways. The Conclusion (page unavailable) links mTOR hyperactivation to reduced autophagy and decreased IRS1 activity, which can lead to insulin resistance. It does not identify oxidatively modified proteins associated with altered glucose metabolism or establish that the mTOR–insulin-resistance findings concern oxidatively modified proteins. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [62] Busciglio, J. & Yankner, B. A. Apoptosis and increased generation of reactive oxygen species in Down’s syndrome neurons in vitro. Nature 378, 776–779 (1995). source
    • cites [65] Tramutola, A. et al. Polyubiquitinylation profile in Down syndrome brain before and after the development of Alzheimer neuropathology. Antioxid. Redox Signal. 26, 280–298 (2017). source

      The Discussion (page unavailable) identifies oxidatively modified energy-metabolism enzymes and a proteostasis protein, HSP60. It also reports mTOR hyperactivation with disturbed autophagosome formation in Down syndrome brain, but does not identify an oxidatively modified mTOR-signaling protein or substantiate the claim of increased insulin resistance. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [66] Vlassenko, A. G. et al. Aerobic glycolysis and tau deposition in preclinical Alzheimer’s disease. Neurobiol. Aging 67, 95–98 (2018). source

      The Introduction discusses brain glucose metabolism, and the Discussion links lower aerobic glycolysis with greater tau deposition in people with preclinical or very mild Alzheimer disease; neither passage addresses oxidatively modified proteins in Down syndrome. Searches for Down syndrome, oxidatively modified proteins, mTOR, autophagy, insulin resistance, and proteostasis found no passage supporting the attributed claim. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    In brains of people with Down syndrome and Down syndrome with Alzheimer disease neuropathology, HNE and protein carbonyl levels are elevated, with greater increases in those with Alzheimer disease.

    “Other biomarkers of increased oxidative damage in the brains of persons with DS and persons with DS with AD neuropathology (DS with AD) include elevated levels of HNE and PC15,42; the increases are greater in people with DS with AD62,65,66.”
    Quote in the paperSubstantial claim2 of 5 sources checked
    • cites [15] Di Domenico, F., Tramutola, A. & Butterfield, D. A. Role of 4-hydroxy-2-nonenal (HNE) in the pathogenesis of Alzheimer disease and other selected age-related neurodegenerative disorders. Free Radic. Biol. Med. 111, 253–261 (2017). source
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source
    • cites [62] Busciglio, J. & Yankner, B. A. Apoptosis and increased generation of reactive oxygen species in Down’s syndrome neurons in vitro. Nature 378, 776–779 (1995). source
    • cites [65] Tramutola, A. et al. Polyubiquitinylation profile in Down syndrome brain before and after the development of Alzheimer neuropathology. Antioxid. Redox Signal. 26, 280–298 (2017). source

      The Discussion (page unavailable) says that many polyubiquitinated proteins in DS brain are also carbonylated and/or HNE-modified. It does not establish that overall HNE and protein carbonyl levels are elevated in both DS and DS/AD brains, or that those levels rise more in DS/AD; the larger increases reported in the Results concern polyubiquitinylation. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [66] Vlassenko, A. G. et al. Aerobic glycolysis and tau deposition in preclinical Alzheimer’s disease. Neurobiol. Aging 67, 95–98 (2018). source

      The Participants and Results sections describe PET measures of aerobic glycolysis, amyloid, and tau in adults with preclinical or mild Alzheimer disease. Our copy does not address Down syndrome or report HNE or protein carbonyl levels; searches for those markers and Down syndrome found no relevant passage. (LLM, conf=0.76)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Besides mTOR activation, insulin resistance can cause neuronal glucose deficiency, leading to reduced glucose metabolism, impaired ATP production, and neuronal dysfunction or death.

    “In addition to mTOR activation, insulin resistance can also result in neuronal glucose deficiency, with consequent decreased glucose metabolism, impaired ATP production, and dysfunction and/or death7,42”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [7] Arnold, S. E. et al. Brain insulin resistance in type 2 diabetes and Alzheimer disease: concepts and conundrums. Nat. Rev. Neurol. 14, 168–181 (2018). This paper is an excellent review of the links between AD, dysfunctional glucose metabolism and diabetes. source

      The “Effects of insulin in neurons” section says insulin can influence neuronal glucose uptake through GLUT4 and promotes neuronal survival. It also says most neuronal glucose uptake occurs through insulin-independent GLUT3. The paper does not establish the claimed sequence from insulin resistance to neuronal glucose deficiency, impaired ATP production, and dysfunction or death. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • May combine two claims.

    Premisecitation

    In Alzheimer disease brain, markers of endoplasmic reticulum stress are elevated and correlate with disease progression.

    “In AD brain, markers of ER stress are elevated and correlate with progression of this disorder53,54,58.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [53] Hashimoto, S. & Saido, T. C. Critical review: involvement of endoplasmic reticulum stress in aetiology of Alzheimer’s disease. Open Biol. 8, 180024 (2018). source

      In “ER stress in AD mouse models and human AD samples,” the review reports elevated ER-stress markers in post-mortem AD brains and an increase in p-PERK-positive neurons with Braak stage. But the same section reports decreases in other markers, calls the human findings inconsistent and poorly reproduced, and says the authors are not convinced that ER stress is generally upregulated in AD brain. The unqualified claim therefore overstates the review's conclusion. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [54] Di Domenico, F., Head, E., Butterfield, D. A. & Perluigi, M. Oxidative stress and proteostasis network: culprit and casualty of Alzheimer’s-like neurodegeneration. Adv. Geriatr. 2014, 1–14 (2014). source

      Section 4 reports increased ER stress in postmortem AD brain, including elevated GRP78/BiP and UPR activation in the temporal cortex and hippocampus. It says these findings occur alongside neurofibrillary tangles and amyloid plaques, but does not report that ER-stress markers correlate with disease progression. Page information is unavailable in our copy. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [58] Wiseman, F. K. et al. Trisomy of human chromosome 21 enhances amyloid-β deposition independently of an extra copy of APP. Brain 141, 2457–2474 (2018). source

      The Results section discusses amyloid-β deposition and cognitive deficits, while Materials and methods > Tissue preparation and western blotting lists APP-related proteins rather than ER-stress markers (pages unavailable). Searches for “ER stress,” “endoplasmic reticulum,” and unfolded-protein-response markers found no passage addressing elevated ER-stress markers in Alzheimer disease brain or their correlation with disease progression. (LLM, conf=0.73)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    Oxidative or nitrosative damage to multiple proteins, including synaptic proteins, very likely contributes to memory problems and other cognitive deficits, reduced neuronal ATP availability, and decreased clearance of abnormal proteins in Alzheimer disease.

    “In summary, oxidative and/or nitrosative damage to multiple proteins, including synaptic proteins is very likely to contribute to the memory problems and other cognitive deficits, reduced ATP availability in neurons, and decreased clearance of abnormal proteins34, creating a “perfect storm” (or sTORm perhaps!) of detrimental cognitive effects in AD9,34,35,41,42.”
    Quote in the paperSubstantial claim2 of 5 sources checked
    • cites [9] Butterfield, D. A., Di Domenico, F. & Barone, E. Elevated risk of type 2 diabetes for development of Alzheimer disease: a key role for oxidative stress in brain. Biochim. Biophys. Acta 1842, 1693–1706 (2014). source

      Section 3.1.1, Protein oxidation (page unavailable), links oxidation of metabolic proteins to reduced ATP production, synaptic dysfunction, and cognitive decline. Section 3 also describes oxidative and nitrosative protein damage. The copy does not establish that the damaged proteins include synaptic proteins or that this damage decreases clearance of abnormal proteins. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [34] Di Domenico, F., Barone, E., Perluigi, M. & Butterfield, D. A. The triangle of death in Alzheimer’s disease brain: the aberrant cross-talk among energy metabolism, mammalian target of rapamycin signaling, and protein homeostasis revealed by redox proteomics. Antioxid. Redox Signal. 26, 364–387 (2017). This paper demonstrates the utility of redox proteomics to increase our understanding of molecular processes involved in neurodegeneration in the pathogenesis and progression of AD. source
    • cites [35] Reed, T. et al. Redox proteomic identification of 4-hydroxy-2-nonenal-modified brain proteins in amnestic mild cognitive impairment: insight into the role of lipid peroxidation in the progression and pathogenesis of Alzheimer’s disease. Neurobiol. Dis. 30, 107–120 (2008). source
    • cites [41] Di Domenico, F. et al. mTOR in Down syndrome: role in Aβ and Tau neuropathology and transition to redox Alzheimer disease-like dementia. Free Radic. Biol. Med. 114, 94–101 (2018). source

      Section 2.1 reports oxidative damage to several protein-clearance components in Down syndrome brain, associated with reduced proteasome activity and autophagosome formation; section 3.1 links oxidative modification of lysosomal proteins to potentially reduced autophagy. The paper does not establish that damage to synaptic proteins causes memory or other cognitive deficits, or that protein oxidation reduces neuronal ATP availability in Alzheimer disease. Its reduced-ATP discussion in section 2.2 concerns neuronal progenitor cells from a Down syndrome mouse model, not that proposed causal link. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • May combine two claims.

    Interpretationcitation

    Both a dose effect from APP triplication and gene-environment interactions likely contribute to Alzheimer-like dementia in Down syndrome.

    “It is likely that both a dose effect of triplication of APP and gene-environment interactions play a role59,60.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [59] Lott, I. T. Neurological phenotypes for Down syndrome across the life span. Prog. Brain Res. 197, 101–121 (2012). source

      The Dementia section links increased APP gene dosage in Down syndrome to early β-amyloid deposition, supporting the APP-dose part of the claim. The introductory section says the neurological phenotype reflects genetic expression and environmental influences, but our copy does not specifically link gene–environment interactions to Alzheimer-like dementia. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [60] Di Domenico, F. et al. Bach1 overexpression in Down syndrome correlates with the alteration of the HO-1/BVR-A system: Insights for transition to Alzheimer disease. J. Alzheimers Dis. 44, 1107–1120 (2015). source

      The Introduction (page unavailable) identifies APP as a chromosome 21 gene and reports that amyloid accumulation in Down syndrome increases with age, leading generally to Alzheimer pathology. It also says Down syndrome phenotypes need not arise exclusively from specific chromosome 21 genes. The paper does not specifically attribute Alzheimer-like dementia to an APP triplication dose effect or to gene–environment interactions. (LLM, conf=0.76)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    One report found high-dose vitamin E delayed nursing-home placement in late-stage AD compared with placebo, but later vitamin E studies were less positive.

    “Following a report of success of high-dose vitamin E in keeping late-stage AD patients out of long-term care facilities longer than patients on a placebo81, other studies with vitamin E have been less impressive70,78,80.”
    Quote in the paperNot a substantial claim2 of 4 sources checked
    • cites [81] Sano, M. et al. A controlled trial of selegiline, α-tocopherol, or both as treatment for Alzheimer disease. N. Engl. J. Med. 336, 1216–1222 (1996). source

      The Discussion reports a significant delay in institutionalization with alpha-tocopherol (vitamin E), and the Methods specify a high dose of 2,000 IU daily in a placebo-controlled trial. The participants had moderately severe Alzheimer’s disease (Clinical Dementia Rating 2), not late-stage disease; severe dementia was a possible study outcome. The statement about later studies is cited to other sources, not this paper. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [70] Winblad, B. et al. Defeating Alzheimer’s disease and other dementias: a priority for European science and society. Lancet Neurol. 15, 455–532 (2016). This article provides a comprehensive review of the current state of AD research and prospects for treatment. source
    • cites [78] Polidori, M. C. & Nelles, G. Antioxidant clinical trials in mild cognitive impairment and Alzheimer’s disease-challenges and perspectives. Curr. Pharm. Des. 20, 3083–3092 (2014). source
    • cites [80] Petersen, R. C. et al. Alzheimer’s Disease Cooperative Study Group. Vitamin E and donepezil for the treatment of mild cognitive impairment. N. Engl. J. Med. 352, 2379–2388 (2005). source

  • May combine two claims.

    Findingcitation

    In an AD mouse model, disrupting Nrf2 worsened cognitive deficits, which suggests the Nrf2 system matters in AD.

    “Indeed, impairment of Nrf2 function worsened cognitive defects in a mouse model of AD90, suggesting the importance of the Nrf2 system in AD.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [90] Branca, C. et al. Genetic reduction of Nrf2 exacerbates cognitive deficits in a mouse model of Alzheimer’s disease. Hum. Mol. Genet. 26, 4823–4835 (2017). source

  • May combine two claims.

    Findingcitation

    Polyphenols, especially curcumin, have worked in some AD mouse models but have not yet proved useful in human AD.

    “In vivo use of polyphenols (especially curcumin) in some mouse models of AD has been successful77,87, but this has not (yet) been translated to usefulness in human AD2,70,87,88.”
    Quote in the paperNot a substantial claim3 of 5 sources checked
    • cites [77] Perluigi, M. et al. In vivo protective effects of ferulic acid ethyl ester against amyloid β-peptide (1–42)-induced oxidative stress. J. Neurosci. Res. 84, 418–426 (2006). source
    • cites [87] Begum, A. N. et al. Curcumin structure-function, bioavailability, and efficacy in models of neuroinflammation and Alzheimer’s disease. J. Pharmacol. Exp. Ther. 326, 196–208 (2008). source

      The Results report reduced plaque pathology in curcumin-fed Tg2576 mice. The Discussion says low plasma levels after oral dosing in humans predict limited clinical translation, but it does not establish that curcumin has not proved useful in human Alzheimer’s disease. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [2] Martins, R. N. et al. Alzheimer’s disease: a journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies—gains from AIBL and DIAN cohort studies. J. Alzheimers Dis. 62, 965–992 (2018). This article provides a detailed review of how cohort studies have contributed to our understanding of AD. source

      The Diet section (page unavailable) reports that animal studies suggest curcumin may influence brain function and dementia development, and that clinical studies in humans with AD have failed to find significant improvement with curcumin supplementation. It does not specify successful treatment in AD mouse models, and its description of the animal evidence is more cautious than the claim. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [70] Winblad, B. et al. Defeating Alzheimer’s disease and other dementias: a priority for European science and society. Lancet Neurol. 15, 455–532 (2016). This article provides a comprehensive review of the current state of AD research and prospects for treatment. source
    • cites [88] Nelson, K. M. et al. The essential medicinal chemistry of curcumin. J. Med. Chem. 60, 1620–1637 (2017). source

  • May combine two claims.

    Premisecitation

    α-Tocopherol traps lipid peroxyl radicals well, while γ-tocopherol seems better at scavenging RNS.

    “Although α-tocopherol is efficient in trapping lipid peroxyl radicals, gamma-tocopherol appears more efficient at scavenging RNS species84.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [84] Pei, R., Mah, E., Leonard, S. W., Traber, M. G. & Bruno, R. S. α-Tocopherol supplementation reduces 5-nitro-γ-tocopherol accumulation by decreasing γ-tocopherol in young adult smokers. Free Radic. Res. 49, 1114–1121 (2015). source

      The Introduction (page unavailable) says that, unlike α-tocopherol, γ-tocopherol traps reactive nitrogen species including nitrogen dioxide and peroxynitrite. That supports the comparative RNS claim. Our copy does not address α-tocopherol's efficiency at trapping lipid peroxyl radicals, so that part of the sentence is unsupported. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Nrf2 is widely expressed in animal tissues but is mostly kept inactive in the cytosol by binding to Keap1, which also promotes its rapid proteasomal degradation.

    “Nrf2 is widely expressed in animal tissues but most of it is kept in an inactive form, largely in the cytosol, by binding to the Keap1 (Kelch-like erythroid cell-derived protein with CNC-homology associated protein 1) protein, which also promotes its rapid degradation by the proteasome8,89.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [89] Ma, Q. & He, X. Molecular basis of electrophilic and oxidative defence: promises and perils of Nrf2. Pharmacol. Rev. 62, 1055–1081 (2012). source

  • May combine two claims.

    Findingcitation

    In AD and MCI brain, BVR-A is nitrosatively modified and dysfunctional, and its loss promotes insulin resistance.

    “BVR-A is nitrosatively modified and dysfunctional in AD and MCI brain100, and its impairment promotes insulin resistance101.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [100] Barone, E., Di Domenico, F., Mancuso, C. & Butterfield, D. A. The Janus face of the heme oxygenase/biliverdin reductase system in Alzheimer disease: it’s time for reconciliation. Neurobiol. Dis. 62, 144–159 (2014). source
    • cites [101] Barone, E. et al. Impairment of biliverdin reductase-A promotes brain insulin resistance in Alzheimer disease: a new paradigm. Free Radic. Biol. Med. 91, 127–142 (2016). source

  • May combine two claims.

    Findingcitation

    Among asymptomatic DIAN participants, the earliest detectable pathology is Aβ aggregate deposition, then reduced glucose metabolism, and finally thinning of key brain regions.

    “The authors demonstrated that the first detectable pathological change in asymptomatic persons in the DIAN network is deposition of Aβ aggregates (which would imply membrane-resident oligomers that would lead to oxidative damage), followed by decreased glucose metabolism, and finally thinning of key brain areas116.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [116] Gordon, B. A. et al. Spatial patterns of neuroimaging biomarker change in individuals from families with autosomal dominant Alzheimer’s disease: a longitudinal study. Lancet Neurol. 17, 241–250 (2018). This paper reports longitudinal PET and MRI results on brains in persons with autosomal dominantly inherited AD obtained regularly 22 years before up to 3 years after the onset of AD symptoms and demonstrates the temporal order of brain pathology observed prior to symptoms. source

  • May combine two claims.

    Findingcitation

    In 3xTg AD mice, intranasal insulin lowered brain nitrosative stress, tau phosphorylation, and Aβ oligomers and improved cognition; these effects required BVR-A activity.

    “Recently, intranasal treatment of a 3 X Tg mice model of AD with insulin showed a significant reduction of brain nitrosative stress, tau phosphorylation, and Aβ oligomers coupled to improved cognition, and these effects were dependent on the activity of biliverdin reductase-A (BVR-A)99,100.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [99] Barone, E. et al. Biliverdin reductase-A mediates the beneficial effects of intranasal insulin in Alzheimer disease. Mol. Neurobiol. https://doi.org/10.1007/s12035-018-1231-5 (2018). This paper improves our mechanistic understanding of the beneficial effects of intranasal insulin in the cognitive improvement of patients with AD and MCI by demonstrating in the 3xTg mouse model of AD that BVRA was prevented from early impairment in adult mice, or rescued from damage in aged mice, following intranasal insulin that was correlated with improved insulin signalling, decreased nitrosative stress an source
    • cites [100] Barone, E., Di Domenico, F., Mancuso, C. & Butterfield, D. A. The Janus face of the heme oxygenase/biliverdin reductase system in Alzheimer disease: it’s time for reconciliation. Neurobiol. Dis. 62, 144–159 (2014). source

      The ‘Reconciliation of the two hypotheses’ section reports reduced nitrosative-stress markers and improved cognition after atorvastatin treatment in aged beagles, not intranasal insulin in 3xTg AD mice. Searches for intranasal insulin and the claimed mouse outcomes found no passage in our copy addressing that experiment or showing that its effects required BVR-A activity; the passages have no page numbers. (LLM, conf=0.77)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    In human ApoE gene-targeted female replacement mice, apoE status affects brain glucose and ketone metabolism, and apoE4 is the most harmful for glucose metabolism.

    “Studies on human ApoE gene-targeted female replacement mice show that apoE status appears to influence brain glucose and ketone metabolism, with the apoE4 allele being the most deleterious for the former103.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [103] Wu, L., Zhang, X. & Zhao, L. Human ApoE isoforms differentially modulate brain glucose and ketone body metabolism: implications for Alzheimer’s disease risk reduction and early intervention. J. Neurosci. 38, 6665–6681 (2018). source

  • May combine two claims.

    Premisecitation

    BVR-A is both a reductase and a kinase that can phosphorylate insulin receptor substrate-1.

    “BVR-A, in addition to being a reductase, is a kinase that can phosphorylate insulin receptor substrate-1100.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [100] Barone, E., Di Domenico, F., Mancuso, C. & Butterfield, D. A. The Janus face of the heme oxygenase/biliverdin reductase system in Alzheimer disease: it’s time for reconciliation. Neurobiol. Dis. 62, 144–159 (2014). source

      The overview’s “HO by-products” section states that BVR-A reduces biliverdin to bilirubin and is also a serine/threonine/tyrosine kinase. It does not say that BVR-A phosphorylates insulin receptor substrate-1; instead, it describes phosphorylation of BVR-A by the insulin receptor kinase. Page numbers are unavailable in our copy. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    Atorvastatin and many other statins cross the blood-brain barrier poorly, yet atorvastatin use is linked to lower AD risk.

    “Many statins, including atorvastatin, do not penetrate the blood-brain barrier (BBB) significantly, yet atorvastatin use is associated with lowered risk of developing AD113,114.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [113] Butterfield, D. A., Barone, E. & Mancuso, C. Cholesterol-independent neuroprotective and neurotoxic activities of statins: perspectives for statin use in Alzheimer disease and other age-related neurodegenerative disorders. Pharmacol. Res. 64, 180–186 (2011). source

      Section 3, “Statins and dementia” (page unavailable), reports that early observational studies linked statin use with reduced risk of developing dementia, including AD, but does not identify atorvastatin specifically for that association. Its “Ability to cross membranes” subsection describes atorvastatin as having intermediate lipophilicity and discusses how that may affect the fraction reaching the brain; it does not say that atorvastatin or many other statins cross the BBB poorly. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [114] Barone, E. et al. Biliverdin reductase-A: a novel drug target for atorvastatin in a dog preclinical model of Alzheimer disease. J. Neurochem. 120, 135–146 (2012). source

  • May combine two claims.

    Findingcitation

    Both HO-1 and BVR-A are oxidatively damaged in aMCI and AD brain.

    “Both HO-1 and BVR-A are oxidatively damaged in aMCI and AD brain100.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [100] Barone, E., Di Domenico, F., Mancuso, C. & Butterfield, D. A. The Janus face of the heme oxygenase/biliverdin reductase system in Alzheimer disease: it’s time for reconciliation. Neurobiol. Dis. 62, 144–159 (2014). source

  • May combine two claims.

    Findingcitation

    The two-year FINGER trial combined diet, exercise, cognitive training, and management of metabolic and vascular risks; it reported cognitive benefits even in apoE4 carriers.

    “Positive effects on cognition were reported108,110 even in subjects with the apoE4 allele110.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [108] Solomon, A. et al. Effect of the Apolipoprotein E genotype on cognitive change during a multidomain lifestyle intervention: a subgroup analysis of a randomized clinical trial. JAMA Neurol. 75, 462–470 (2018). source
    • cites [110] Fyfe, I. APOE ε4 affects cognitive decline but does not block benefits of healthy lifestyle. Nat. Rev. Neurol. 14, 25 (2018). source

  • May combine two claims.

    Findingcitation

    Craft and colleagues found that short-term intranasal insulin improved cognition and lowered neurotoxic Aβ42 in early AD patients.

    “Craft and co-workers investigated insulin resistance in AD7,38 and reported improved cognition in early AD patients and decreased levels of neurotoxic Aβ42 following a short-term treatment with intranasal insulin98.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [98] Claxton, A. et al. Sex and ApoE genotype differences in treatment response to two doses of intranasal insulin in adults with mild cognitive impairment or Alzheimer’s disease. J. Alzheimers Dis. 35, 789–797 (2013). source

      The Introduction (page unavailable) reports improved memory and cognitive scores after intranasal insulin in people with early AD or MCI. It says amyloid-β levels may be modulated, but neither the Introduction nor the retrieved passages report a decrease in Aβ42; that part of the claim is unsupported. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Interpretationcitation

    A recent paper is highly consistent with this sequence of events.

    “A recent paper is highly consistent with sequence of events116.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [116] Gordon, B. A. et al. Spatial patterns of neuroimaging biomarker change in individuals from families with autosomal dominant Alzheimer’s disease: a longitudinal study. Lancet Neurol. 17, 241–250 (2018). This paper reports longitudinal PET and MRI results on brains in persons with autosomal dominantly inherited AD obtained regularly 22 years before up to 3 years after the onset of AD symptoms and demonstrates the temporal order of brain pathology observed prior to symptoms. source

  • May combine two claims.

    Interpretationcitation

    Even though atorvastatin is not a direct antioxidant and cannot cross the BBB, it produces antioxidant-like effects in the brain.

    “It also suggests that atorvastatin, although not a direct antioxidant and not able to cross the BBB, leads to antioxidant-like effects in brain100.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [100] Barone, E., Di Domenico, F., Mancuso, C. & Butterfield, D. A. The Janus face of the heme oxygenase/biliverdin reductase system in Alzheimer disease: it’s time for reconciliation. Neurobiol. Dis. 62, 144–159 (2014). source

      In “Reconciliation of the two hypotheses” (page unavailable), the paper reports reduced brain oxidative-stress markers after atorvastatin treatment in aged beagles, supporting antioxidant-like effects in that preclinical model. It says atorvastatin can cross the BBB “only to a minute extent,” not that it cannot cross at all; the passage also does not explicitly establish that atorvastatin is not a direct antioxidant. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    Curcumin is a weak antioxidant in vitro and degrades readily, including in cell culture, into various active products.

    “But, curcumin is actually a poor antioxidant in vitro8 and readily breaks down, for example in cell culture91, to a range of biologically active products.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [91] Long, L. H., Hoi, A. & Halliwell, B. Instability of, and generation of hydrogen peroxide by, phenolic compounds in cell culture media. Arch. Biochem. Biophys. 501, 162–169 (2010). source

  • May combine two claims.

    Findingcitation

    In Down syndrome, elevated oxidative stress and mTOR activation inhibit autophagy, causing accumulation of neuronal detritus and formation of AD-like senile plaques.

    “Elevated oxidative stress and mTOR activation with consequent inhibited autophagy that results in elevated levels of neuronal detritus are observed, and AD-like senile plaques form.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • May combine two claims.

    Findingcitation

    In aged beagles, atorvastatin protected BVR-A from oxidation, raised HO-1, and reduced brain oxidative damage.

    “Atorvastatin given to aged beagle dogs protected against oxidation of BVR-A and this statin increased HO-1 levels, whereas oxidative damage levels in brain were lowered114.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [114] Barone, E. et al. Biliverdin reductase-A: a novel drug target for atorvastatin in a dog preclinical model of Alzheimer disease. J. Neurochem. 120, 135–146 (2012). source

  • May combine two claims.

    Premisecitation

    Protein carbonyl levels are increased in Alzheimer disease brain regions rich in amyloid beta-containing plaques but remain normal in regions without such plaques.

    “levels of protein carbonyls (PC) are elevated in AD in brain regions that are rich in amyloid beta-peptide (Aβ)-containing senile plaques (Table 1), but at normal levels from brain regions devoid of Aβ-rich plaques19.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] Hensley, K. et al. Brain regional correspondence between Alzheimer’s disease histopathology and biomarkers of protein oxidation. J. Neurochem. 65, 2146–2156 (1995). source

  • May combine two claims.

    Interpretationreasoning

    Reduced ATP production impairs ATP-dependent cognitive processes and leads to synaptic dysfunction, neuronal death, and thinning of key brain regions.

    “Consequently, ATP-requiring processes for cognitive function are impaired, and synaptic dysfunction and neuronal death result, with ensuing thinning of key brain areas.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    About 15% of people with amnestic mild cognitive impairment progress to Alzheimer disease each year.

    “It has been estimated that approximately 15 percent of people with aMCI progress to AD annually3.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Markesbery, W. R. Neuropathologic alterations in mild cognitive impairment: a review. J. Alzheimers Dis. 19, 221–228 (2010). source

  • May combine two claims.

    Interpretationreasoning

    Increased oxidative and nitrosative damage probably causes glucose dysmetabolism, loss of ion gradients, impaired action potentials, and calcium dyshomeostasis.

    “Consequences of this increased oxidative and nitrosative damage are likely to include glucose dysmetabolism (see section on oxidative damage below) and loss of ion gradients with resulting impaired action potentials and Ca2+ dyshomeostasis”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Large amyloid beta 42 oligomers appear relatively non-toxic, while small oligomers such as dimers or trimers appear highly toxic to synapses.

    “Interestingly, large oligomers of Aβ42, which would have difficulty solubilizing in the neuronal lipid bilayer, seem relatively non-toxic, whereas small oligomers of Aβ42 (for example, dimers or trimers that easily enter lipid bilayers) appear highly toxic to synapses33.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] Yang, T., Li, S., Xu, H., Walsh, D. M. & Selkoe, D. J. Large soluble oligomers of amyloid β-protein from Alzheimer brain are far less neuroactive than the smaller oligomers to which they dissociate. J. Neurosci. 37, 152–163 (2017). source

  • May combine two claims.

    Interpretationcitation

    Excess intraneuronal free calcium can impair microtubule assembly, reducing anterograde and retrograde transport of mitochondria and neurotransmitter vesicles, starving presynaptic terminals of energy and decreasing neurotransmission.

    “Excess intra-neuronal free Ca2+ can also cause loss of fidelity of microtubule assembly40, with consequent decreased anterograde and retrograde transport of mitochondria and neurotransmitter vesicles, starving presynaptic terminals of energy and decreasing neurotransmission.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [40] Tramutola, A. et al. Alteration of mTOR signaling occurs early in the progression of Alzheimer disease (AD): analysis of brain from subjects with pre-clinical AD, amnestic mild cognitive impairment, and late-stage AD. J. Neurochem. 133, 739–749 (2015). This paper contains the first report of mTORC1 activation and consequent markers of insulin resistance and inhibition of autophagy in brains of subjects with aMCI, consistent with the notion that mTORC1 activation occurs well before dementia in the progression of AD and reflects glucose dysmetabolism early in the disease. source

  • May combine two claims.

    Interpretationreasoning

    Reduced ATP impairs the neuron's ability to maintain ionic gradients, which hinders action potential generation and propagation and therefore neurotransmission.

    “decreased ATP will diminish the neuron’s ability to maintain ionic gradients, hindering production and propagation of action potentials and therefore neurotransmission.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    Loss of ion gradients allows extracellular calcium to enter, raising intracellular free calcium and stimulating calcium-dependent endonuclease, phospholipase, and proteinase activities, contributing to synaptic dysfunction and neuronal death.

    “Moreover, loss of ion gradients can allow extracellular Ca2+ to enter, which can further raise intracellular free Ca2+ levels, stimulating Ca2+-dependent endonuclease, phospholipase, and proteinase activities8, contributing to synaptic dysfunction and eventual neuronal death.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source

  • May combine two claims.

    Premisecitation

    Oxidative stress raises intracellular free calcium levels, which can lead to several harmful effects.

    “because oxidative stress is well known to raise intracellular free Ca2+ levels, from which several deleterious consequences can follow8.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source

  • May combine two claims.

    Interpretationcitation

    Excess calcium can overwhelm endoplasmic reticulum and mitochondrial calcium buffering, causing mitochondrial swelling, opening of the permeability transition pore, release of cytochrome c and apoptosis inducing factor-1, and neuronal apoptotic death.

    “Excess Ca2+ can saturate the ability of endoplasmic reticulum (ER) and mitochondria to buffer and cycle Ca2+, causing swelling of the latter with consequent opening of the mitochondrial permeability transition pore, leading to release of cytochrome c and apoptosis inducing factor-1, provoking neuronal apoptotic death39.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [39] Pirollet, F., Margolis, R. L. & Job, D. Ca2+-calmodulin regulated effectors of microtubule stability in neuronal tissues. Biochim. Biophys. Acta 1160, 113–119 (1992). source

  • May combine two claims.

    Interpretationreasoning

    Oxidative modification is likely a major cause of inefficient glucose utilization because it almost always reduces the activity of glucose-metabolizing enzymes.

    “A major contributor to inefficient glucose utilization may well be oxidative modification, which almost always leads to decreased activity of enzymes involved in glucose metabolism (Figure 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    Failure of oxidatively damaged UCH L1 in amnestic mild cognitive impairment and Alzheimer disease brains leads to accumulation of ubiquitinylated proteins, reduced proteasome function, and accumulation of damaged, aggregated proteins.

    “the failure of oxidatively damaged UCH L1 to perform its function in aMCI and AD brains leads to accumulation of ubiquitinylated proteins, decreased proteasome function, and subsequent accumulation of damaged, aggregated proteins55.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] Choi, J. et al. Oxidative modifications and down-regulation of ubiquitin caryl-terminal hydrolase L1 associated with idiopathic Parkinson’s and Alzheimer’s diseases. J. Biol. Chem. 279, 13256–13264 (2004). source

  • May combine two claims.

    Interpretationreasoning

    These calcium-related processes lead to synaptic dysfunction, neuronal death, and ultimately cognitive dysfunction.

    “This in turn leads to synaptic dysfunction, neuronal death, and ultimately to cognitive dysfunction.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    The genetic abnormalities underlying Down syndrome drive mechanisms similar to those in AD, providing insights into DS, aMCI, and AD and suggesting novel therapeutic targets.

    “To summarize, the genetic abnormalities underlying DS drive mechanisms similar to those in AD, providing insights not only into DS but also into aMCI and AD and also suggesting novel therapeutic targets and approaches67.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [67] Caraci, F. et al. Searching for new pharmacological targets for the treatment of Alzheimer’s disease in Down syndrome. Eur. J. Pharmacol. 817, 7–19 (2017). source

  • May combine two claims.

    Interpretationreasoning

    If vitamin E fails to lower brain oxidative damage substantially, it cannot be effective against MCI or AD.

    “If administered vitamin E does not decrease oxidative damage in the brain significantly, then it will not be effective against MCI or AD.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    In Down syndrome, Aβ is among the non-degraded moieties, and its accumulation increases oxidative damage, activates RAGE, and activates mTOR, perpetuating the cycle.

    “Among the non-degraded moieties is Aβ itself, whose accumulation leads to more oxidative damage, RAGE activation, and activation of mTOR, continuing the vicious cycle.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • May combine two claims.

    Interpretationcitation

    Because oxidative damage is central to aMCI, PCAD, and AD pathology, blocking it ought to help therapeutically.

    “The key role of oxidative damage in the pathology of aMCI, PCAD and AD suggests that inhibiting it should have therapeutic benefit8,11.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [11] Halliwell, B. Oxidative stress and neurodegeneration: where are we now? J. Neurochem. 97, 1634–1658 (2006). source

  • May combine two claims.

    Interpretationcitation

    Hyperphosphorylated tau destabilizes microtubules, impairing mitochondrial trafficking and causing presynaptic energy deficits.

    “Hyperphosphorylated tau leads to destabilization of microtubules, affecting mitochondrial trafficking thus leading to presynaptic energy deficits.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [42] Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer’s disease: inseparable partners in a multifactorial disease. FASEB J. 31, 2729–2743 (2017). source

  • May combine two claims.

    Premisereasoning

    Replacing labile hydrogens with deuterium makes fatty acid chains harder to peroxidize, because ROS abstract deuterium less easily and the C-D bond is stronger than C-H.

    “Chains in which labile hydrogen atoms are replaced by deuterium atoms are more resistant to peroxidation. This is because abstraction of deuterium by ROS is harder, since the C-D bond is much stronger than the C-H bond.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Such oxidative damage generates reactive aldehydes that bind critical brain proteins, altering their shape and reducing their activity in aMCI and AD.

    “This produces reactive aldehydes (Table 1) that bind to critical brain proteins to change their conformation and to lower their activity in aMCI and AD brain.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Presynaptic membranes are especially susceptible to this oxidative damage, which leads to worse learning and memory and eventually dementia.

    “Presynaptic membranes are particularly vulnerable to such oxidative damage, leading to diminished learning and memory and ultimately dementia.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Although aMCI and AD are strongly linked to oxidative damage, they are complex, and other processes probably also drive their pathogenesis and progression.

    “An additional consideration when considering the effectiveness (or lack of it) of antioxidants is that, though aMCI and AD are strongly associated with oxidative damage, they are highly complex disorders, and processes other than oxidative damage are likely to contribute to their pathogenesis and progression.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Lower ATP causes many brain functional changes, including poor membrane potential maintenance and raised intracellular Ca2+, with harmful downstream effects on cell function and survival.

    “Decreased ATP results in numerous changes in brain function, such as impaired maintenance of membrane potentials, and increased intracellular Ca2+ levels leading to detrimental downstream effects on cell function and survival.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    HO-1 oxidizes heme to produce biliverdin, which is reduced by BVR-A to bilirubin, a scavenger of ROS/RNS.

    “The enzyme heme oxygenase 1 (HO-1) oxidizes heme (a pro-oxidant)8 to produce biliverdin, which is reduced by a biliverdin reductase-A (BVR-A) enzyme to bilirubin (a scavenger of ROS/RNS8,101).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [8] Halliwell, B. & Gutteridge, J. M. C. Free Radicals in Biology and Medicine 5th edn (Oxford Univ. Press, 2015). This book provides a thorough and detailed summary of the role of ROS and antioxidants in human health and disease, including neurodegenerative diseases. source
    • cites [101] Barone, E. et al. Impairment of biliverdin reductase-A promotes brain insulin resistance in Alzheimer disease: a new paradigm. Free Radic. Biol. Med. 91, 127–142 (2016). source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    This review's central hypothesis is that oxidative stress from Aβ42 oligomers impairs glucose metabolism, causing synaptic dysfunction and neuronal death that ultimately produce aMCI, PCAD, and AD.

    “The overall hypothesis presented in this review for the pathogenesis and progression of AD is that Aβ42 oligomer-induced oxidative stress impairs glucose metabolism, leading to synaptic dysfunction and eventual neuronal death (demonstrated by thinning of key brain areas), ultimately causing aMCI, PCAD, and AD.”
    Quote in the paperSubstantial claim
64 of 64

  • The paper relies on this without support.

    Preclinical Alzheimer disease is the earliest disease stage, with normal cognition during life but substantial Alzheimer neuropathology at autopsy.

    “Arguably the earliest stage of AD is preclinical AD (PCAD) in which persons have normal cognitive status, but upon death and autopsy their brains display evidence of substantial AD neuropathology.”

  • The paper relies on this without support.

    Amnestic mild cognitive impairment is a prodromal early stage of Alzheimer disease in which Alzheimer neuropathology is present to a lesser degree.

    “Amnestic mild cognitive impairment (aMCI) is a progressive condition in which there is some degree of memory loss and is widely thought to be a prodromal early stage of AD in which AD neuropathology is present, albeit to a lesser degree.”

  • The paper relies on this without support.

    Glucose is the main energy substrate for the brain and is converted to ATP through glycolysis, the TCA cycle, and the electron transport chain.

    “Glucose is normally the major energy source for the brain and is metabolized to ATP via glycolysis, the tricarboxylic acid (TCA) cycle, and the electron transport chain (ETC), as shown in Figure 1.”

  • The paper relies on this without support.

    Neuritic plaques and neurofibrillary tangles contain proteins that have undergone oxidation, glycation, and nitration.

    “For example, neuritic plaques (rich in fibrillar Aβ42 and Aβ40) and neurofibrillary tangles contain oxidized, glycated, and nitrated proteins.”

  • The paper relies on this without support.

    Oxidative damage to DNA can disrupt gene transcription and promoter function, causing reduced transcription of essential genes and mutations.

    “Moreover, oxidative DNA damage can interfere with gene transcription and affect promoter function, which can lead to impaired transcription of essential genes and to mutations.”

  • The paper relies on this without support.

    Oxidative damage to RNA can reduce protein translation and cause premature RNA degradation, further impairing synthesis of essential proteins.

    “Oxidative RNA damage can impair protein translation and the damaged RNA can be prematurely degraded, further impairing synthesis of essential proteins (Table 1).”

  • The paper relies on this without support.

    Exposing neurons to oligomeric amyloid beta causes large calcium increases, oxidative stress, and endoplasmic reticulum stress-dependent neuronal death.

    “Addition of oligomeric Aβ to neurons leads to large elevations in Ca2+ with consequent oxidative stress and ER stress-dependent neuronal death.”

  • The paper relies on this without support.

    Chromosome 21 contains several genes linked to Alzheimer disease and oxidative stress, including APP and beta-secretase-2.

    “There are several genes associated with AD and oxidative stress on chromosome 21, including amyloid precursor protein (APP), from which Aβ arises, and beta-secretase-2, one of the proteinases that act on APP to form Aβ.”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Hydroxyl radical reaction with proteins leads to incorporation of carbonyl functionalities and alterations in protein conformation, normally with loss of function.

    “The former leads to the incorporation of carbonyl functionalities in proteins and alterations in protein conformation (and normally loss of function as a consequence) [8,22,23,24]”

    From Mitochondrial Oxidative and Nitrosative Stress and Alzheimer Disease (2020) · cites this paper as [8]

    The ‘Oxidative Damage is relevant to AD’ section identifies protein carbonyls as markers of oxidative damage, and ‘Contribution of oxidative damage’ says oxidative modification almost always decreases the activity of the glucose-metabolism enzymes it discusses. The concluding remarks link changed protein conformation and reduced activity to reactive aldehydes from lipid peroxidation. Our copy does not establish the claimed sequence specifically for hydroxyl-radical reactions with proteins. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • OH-mediated allylic hydrogen atom abstraction from unsaturated lipid acyl chains initiates lipid peroxidation, leading to highly reactive nucleophilic unsaturated aldehydes such as 4-hydroxynonenal.

    “while OH-mediated allylic hydrogen atom abstraction from unsaturated lipid acyl chains initiates the processes of lipid peroxidation, leading to highly reactive nucleophilic unsaturated aldehydes such as 4-hydroxynonenal (HNE) (Figure 2A) [8,13,25,26,27].”

    From Mitochondrial Oxidative and Nitrosative Stress and Alzheimer Disease (2020) · cites this paper as [8]

    The Deuterated lipids section (page unavailable) says lipid peroxidation involves hydrogen abstraction from unsaturated fatty acid chains, and the Polyphenols section identifies HNE as an unsaturated aldehyde formed during lipid peroxidation. The copy does not specify that OH• performs allylic hydrogen abstraction. It also describes HNE as an electrophile, contrary to the claim that it is nucleophilic. (LLM, conf=0.89)

    Experimental — accuracy not yet measured

  • H2O2 can be decomposed to hydroxyl anion and the highly reactive hydroxyl free radical by Fe2+ or Cu+ in Fenton chemistry.

    “In that case, H2O2, which has zero dipole moments and is therefore neutral and can diffuse into or through bilayers, can be decomposed to hydroxyl anion and the highly reactive hydroxyl free radical by Fe2+ or Cu+ in a process known as Fenton chemistry [8,13].”

    From Mitochondrial Oxidative and Nitrosative Stress and Alzheimer Disease (2020) · cites this paper as [8]

    The section “Oxidative Damage is relevant to AD” describes OH• as highly reactive and H2O2 as less reactive. Our copy does not state that Fe2+ or Cu+ decomposes H2O2 into hydroxyl anion and hydroxyl radical through Fenton chemistry; searches for Fenton chemistry and the metal-ion reaction found no such passage. Page numbers were not available in the indexed copy. (LLM, conf=0.78)

    Experimental — accuracy not yet measured

  • Altered glucose metabolism is associated with Aβ-mediated lipid peroxidation and protein oxidative damage to glycolytic and mitochondrial enzymes, ion-motive ATPases, opening of voltage-gated Ca2+ channels with Ca2+ elevation in endoplasmic reticulum and mitochondria, and consequent neuronal death.

    “evidence was collected for altered glucose metabolism associated with Aβ-mediated lipid peroxidation and protein oxidative damage to glycolytic and mitochondrial enzymes, ion-motive ATPases, the opening of voltage-gated Ca2+ channels with resulting Ca2+ elevation in endoplasmic reticulum and mitochondria, and consequent neuronal death [8,35].”

    From Mitochondrial Oxidative and Nitrosative Stress and Alzheimer Disease (2020) · cites this paper as [8]

    Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

    Experimental — accuracy not yet measured

  • Membrane-resident oligomeric Aβ is present and induces oxidative damage (lipid peroxidation) prior to the detection of Aβ deposition.

    “Accordingly, membrane-resident oligomeric Aβ is present and induces oxidative damage (lipid peroxidation) prior to the detection of Aβ deposition [8]”

    From Mitochondrial Oxidative and Nitrosative Stress and Alzheimer Disease (2020) · cites this paper as [8]

    The Concluding remarks (page unavailable) state that small membrane-solubilized Aβ42 oligomers promote oxidative damage, including lipid peroxidation. But the review calls Aβ aggregate deposition the first detectable pathological change in the DIAN cohort and says membrane-resident oligomers and their damage are implied, not that lipid peroxidation was detected before deposition. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conflicting estimates of when AD pathology begins

    Minor

    The introduction places the onset of pathology up to two decades before symptoms, while the conclusion says it begins at least two decades before symptoms. Those descriptions give opposing bounds on the interval.

1 of 1

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.1038/nature07767

    Info

    The cited work was retracted on 2023-12-18 (notice 10.1038/s41586-023-06943-3), not before this paper was published (2019-02-08).

    Cited work 10.1038/nature07767 · retracted 2023-12-18 · notice 10.1038/s41586-023-06943-3 · this paper published 2019-02-08

1 of 1

Cites

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Related

Authors
Butterfield, D. A., & Halliwell, B.
Affiliations
  • University of Kentucky (US)
  • National University of Singapore (SG)
Corresponding author
Halliwell, Barry
ORCID
Venue
Nature Reviews Neuroscience
Publisher
Springer Science and Business Media LLC
Published
2019-02-08
Volume
20
Issue
3
Pages
148-160
ISSN
  • 1471-003X (ISSN-L)
  • 1471-0048
DOI
10.1038/s41583-019-0132-6
PMC
PMC9382875
OpenAlex
W2911493122
Cited by
1,954
References
122
Citations by year
2026: 322 · 2025: 343 · 2024: 297 · 2023: 263 · 2022: 291 · 2021: 229 · 2020: 166 · 2019: 42 · 2012: 1
FWCI
21.87
Type
journal article
Language
en
Open access
Licence
Locations
  • Nature reviews. Neuroscience (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Medical Research Council
  • National Institute on Aging (R01AG060056)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Neurology › Neurological Disease Mechanisms and Treatments
Keywords
Alzheimer's disease, oxidative stress, brain glucose metabolism, amnestic mild cognitive impairment, glycolysis, TCA cycle, ATP production, proteostasis, synaptic dysfunction, neuronal cell death, age-related dementia, pharmacological interventions
MeSH terms
Alzheimer Disease, Animals, Brain, Glycolysis, Humans, Glucose Intolerance, Oxidative Stress, Disease Progression

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read under definition version 3 (extract-v3) on 2026-09-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-09-28.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

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